
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>用循环将三个DIV变成红色</title>
    <style>
        #outer{width:330px;height:100px;margin:10px auto;}
        #outer div{float:left;width:100px;height:100px;margin:0 5px;background:black;}
    </style>
    <script>
        window.onload = function ()
        {
            var oDiv = document.getElementById("outer").getElementsByTagName("div");
            var oBtn = document.getElementsByTagName("button")[0];
            oBtn.onclick = function ()
            {
                for(var i = 0; i < oDiv.length; i++) oDiv[i].style.background = "red";
            }
        }
    </script>
</head>
<body>
<center><button>点击将DIV变成红色</button></center>
<div id="outer">
    <div></div>
    <div></div>
    <div></div>
</div>
</body>
</html>
